/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.nexmark.queries;



import com.bff.gaia.unified.sdk.nexmark.NexmarkConfiguration;

import com.bff.gaia.unified.sdk.nexmark.model.Bid;

import com.bff.gaia.unified.sdk.nexmark.model.Event;

import com.bff.gaia.unified.sdk.transforms.DoFn;

import com.bff.gaia.unified.sdk.transforms.Max;

import com.bff.gaia.unified.sdk.transforms.ParDo;

import com.bff.gaia.unified.sdk.transforms.windowing.FixedWindows;

import com.bff.gaia.unified.sdk.transforms.windowing.Window;

import com.bff.gaia.unified.sdk.values.PCollection;

import com.bff.gaia.unified.sdk.values.PCollectionView;

import org.joda.time.Duration;



/**

 * Query 7, 'Highest Bid'. Select the bids with the highest bid price in the last minute. In CQL

 * syntax:

 *

 * <pre>

 * SELECT Rstream(B.auction, B.price, B.bidder)

 * FROM Bid [RANGE 1 MINUTE SLIDE 1 MINUTE] B

 * WHERE B.price = (SELECT MAX(B1.price)

 *                  FROM BID [RANGE 1 MINUTE SLIDE 1 MINUTE] B1);

 * </pre>

 *

 * <p>We will use a shorter window to help make testing easier. We'll also implement this using a

 * side-input in order to exercise that functionality. (A combiner, as used in Query 5, is a more

 * efficient approach.).

 */

public class Query7 extends NexmarkQueryTransform<Bid> {

  private final NexmarkConfiguration configuration;



  public Query7(NexmarkConfiguration configuration) {

    super("Query7");

    this.configuration = configuration;

  }



  @Override

  public PCollection<Bid> expand(PCollection<Event> events) {

    // Window the bids.

    PCollection<Bid> slidingBids =

        events

            .apply(NexmarkQueryUtil.JUST_BIDS)

            .apply(

                Window.into(

                    FixedWindows.of(Duration.standardSeconds(configuration.windowSizeSec))));



    // Find the largest price in all bids.

    // NOTE: It would be more efficient to write this query much as we did for Query5, using

    // a binary combiner to accumulate the bids with maximal price. As written this query

    // requires an additional scan per window, with the associated cost of snapshotted state and

    // its I/O. We'll keep this implementation since it illustrates the use of side inputs.

    final PCollectionView<Long> maxPriceView =

        slidingBids

            .apply("BidToPrice", NexmarkQueryUtil.BID_TO_PRICE)

            .apply(Max.longsGlobally().withFanout(configuration.fanout).asSingletonView());



    return slidingBids

        // Select all bids which have that maximum price (there may be more than one).

        .apply(

        name + ".Select",

        ParDo.of(

                new DoFn<Bid, Bid>() {

                  @ProcessElement

                  public void processElement(ProcessContext c) {

                    long maxPrice = c.sideInput(maxPriceView);

                    Bid bid = c.element();

                    if (bid.price == maxPrice) {

                      c.output(bid);

                    }

                  }

                })

            .withSideInputs(maxPriceView));

  }

}